First of all I would like to explain that this is the last question I need to answer to complete an assignment that consisted of 20 University of Waterloo SIN Contest questions. This question is from the 1999 SIN contest. I would ask my Physics teacher for help but it is now the weekend and the assignment is due on Monday so I have come here looking for aid.(adsbygoogle = window.adsbygoogle || []).push({});

PS. The question itself is kind of a Canadian politics joke.

1. The problem statement, all variables and given/known data

Big Jean Chretien. in a liberal mood. throws a carton of pepper spray at Lucien Bouchard. (Assault by pepper?). Lucien catches the carton, and hangs onto it, of course. (Has he ever returned a federal gift?). Since both men were initially standing at rest on a frictionless horizontal ice surface, this exchange causes them to separate. Each man has a mass of 100 kg, the carton has a mass of 20 kg, and the carton left Jean's hands with a horizontal velocity of 10 m/s relative to Jean's body. Calculate the final relative separation speed between the two men. (Answer in m/s).

(a) 2.7

(b) 3.1

(d) 7.1

(e) 8.9

(c) 5.2

2. Relevant equations

Pt = Pt'

Pt' = P1' + P2' (Similar to Pt)

P1 = m1v1 (Similar to P2, P1', P2' etc...)

m1v1 + m2v2 = m1v1' + m2v2'

P = Momentum

m = Mass

v = Velocity

3. The attempt at a solution

Ok so, the first thing i did is find the speed of Lucien Bouchard. Since the 20kg projectile sticks to him once he catches it then we know that v1' = v2' = v'

Knowing that:

Pt = Pt'

m1v1 + m2v2 = m1v1' + m2v2'

m1v1 + m2v2 = m1v' + m2v'

m1v1 + m2v2 = v'(m1 + m2)

(20)(10) + (100)(0) = v'(20 + 100)

v' = 1.67 m/s

Now to find the speed of Jean Chretien. To find this one I used a similar equation but since he is not moving before he throws the projectile Pt = 0.

Pt = Pt'

0 = Pt'

0 = m1v1' + m2v2'

-m1v1' = m2v2'

-(100)v1' = (20)(10)

v1' = -2 m/s

This would give me a final relative separation speed of:

v = v' - (v1')

v = (1.67) - (-2)

v = 3.67 m/s

And since this is not one of the multiple choice answers it means that I did something wrong somewhere.

Any help would be greatly appreciated, especially before monday . And if there is anything you guys don't understand then please ask and I will explain more thoroughly.

Attached is a .pdf file with a scan of the question and my rough work.

Thanks in advance.

- Stahs

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# Momentum and Conservation of Momentum Problem

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